The Avenger (1960 film)

The Avenger German Der Rcher is a 1960 West German crime film directed by Karl Anton and starring Heinz Drache.

When Ruth Sanders Ina Duscha, the niece of the man killed and the last person to see him alive, is located as an extra working on location, Brixan discovers a page of a script that has been written on the same typewriter as the Executioners letters. Consequently, Brixan believes that the Executioner is among the cast, crew, or parties involved in the film shoot.

Source: Wikipedia